Recently, as oil prices have increased, a demand for improving fuel efficiency is increased, and vehicle manufacturers have been made an effort to develop a technology for improving fuel efficiency of an engine. Technical skills are concentrated on development of a turbo gasoline direct injected (GDI) vehicle capable of increasing output and downsizing the engine as one of such technology development direction.
To this end, a turbo system of a supercharging type like Patent Document 1 has been suggested. The turbo system rotates a turbine using exhaust gas and supercharges fresh air by a compressor coaxially connected to the turbine, thereby improving engine torque and fuel efficiency.
Meanwhile, an electronic waste gate actuator (EWGA) is installed in a waste gate turbo-charger to serve to control a waste gate valve of the turbo-charger depending on operation conditions. The EWGA is controlled by receiving a signal from a driver IC of an engine control unit (ECU), and diagnosing a failure of a power stage through the driver IC for the actuator is essentially required in a turbo vehicle in which the EWGA is installed according to safety laws. The power stage allows power to flow between electronic equipment in a vehicle.
Meanwhile, since whether a failure occurs is determined based on a current or a voltage in a circuit, a possibility that information on the failure of the power stage present in the EWGA driver IC is transferred even in a case of signal noise, not an actual failure may not be ruled out.
Therefore, in a case of the turbo vehicle using the EWGA that is currently on the market, as illustrated in FIG. 4, whether a failure occurs is not diagnosed by directly using the failure information of the EWGA driver IC, but only when there is a problem in controllability during driving (S30), the failure information is used to determine (S40) whether the failure of the power stage occurs.
According to the related art, the waste gate valve is driven (S20) in order to use the turbo at the time of rapid acceleration during driving or at the tine of driving at high speed. In this case, when it is determined that the valve is not normally driven (S30), whether the information on the failure of the power stage transmitted from the EWGA driver IC is present is confirmed (S40), and if the failure information is present, it is diagnosed that the failure of the power stage occurs (S60).
However, according to the related art, in a case in which the turbo is not driven since the rapid acceleration does not occur or high speed driving is not performed during a driving cycle, the failure of the power stage of the EWGA may not be diagnosed even when the failure of the power stage of the EWGA actually occurs. In this case, a severe failure may occur even in the ECU due to the failure of the power stage of the EWGA.
Further, at the time of EWGA position learning, if a learning result is abnormal, whether the failure of the power stage occurs is not considered, thus even when the valve is normal, the valve may be unnecessarily replaced, such that additional expense is generated.
The patent document Korean Patent No. 10-1552061 (Sep. 10, 2015) is related to subject matter disclosed herein.